Examine the potentiometer circuit arranged as shown in the figure. The potentiometer wire has a length of 600 cm . Determine the distance from point A where the jockey must touch the wire to achieve zero deflection in the galvanometer.

Step-by-step solution

The total resistance of the primary circuit is the sum of the internal resistance of the battery and the resistance of the potentiometer wire: R_ eq = r + R = r + 15r = 16r The current flowing through the primary circuit is: I = E R_ eq = E 16r The potential difference across the entire potentiometer wire of length L is: V = I R = ( E 16r ) 15r = 15 E 16 The potential gradient (potential drop per unit length) along the potentiometer wire is: k = V L = 15 E 16L For zero deflection in the galvanometer, the potential